


Trapped Souls (Chara x Sans)

by Fenrirwolfe



Category: Undertale
Genre: But I m not sure, Chara & Sans - Freeform, Chara (Female), Eventual Smut, F/F, F/M, Gen, Love - Hate Relationship, Murderbones, There's not enough Sans/Chara here, Undertale Fanfiction, Undertale Spoilers, possibly, sinners rejoice, there will be smut
Language: English
Status: In-Progress
Published: 2016-03-29
Updated: 2016-08-08
Packaged: 2018-05-29 21:39:49
Rating: Mature
Warnings: Graphic Depictions Of Violence, Major Character Death
Chapters: 9
Words: 12,831
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/6394867
Author URL: https://archiveofourown.org/users/Fenrirwolfe/pseuds/Fenrirwolfe
Summary: <blockquote class="userstuff">
              <p>Sans knew Chara from the beginning -he just forgotten all about her.</p>
            </blockquote>





	1. Chapter 1

“*why’d you kill him then?” Sans growled at the pathetic form sprawled on the golden tiles of the Judgement Hall, eye socket glowing cyan and yellow. Sans used to love this place – loved how the light catches the tinted windows, mimicking the illusion of sunlight. Ironically, the one place he loved was going to be his final resting place.

_Heh,_ Sans thought _this is what I get for being a lazybones._

He was breathing heavily, the weight of his previous attacks catching up on him. He couldn’t afford to mess it up now, not when the brat had gotten this far. It was the 20 th battle in a row and the kid was getting farther and farther each reset. Sans knew he shouldn’t say anything outside the pre-loaded conversation but he couldn’t help it; it was getting harder to keep his loathing inside; he just had to know.

Frisk, no, this wasn’t Frisk- this was a murderous child filled with nothing but greed and hate, possessing his friend’s body to decimate the Underground to dust. This thing was a parasite in his friend’s body, forcing Sans to kill them over, and over and over again.

Fighting this thing was pointless – it would just RESET and he’d be back from where he started, only more tired and seething with anger – but he was the last line of defense, it was either he kept fighting till it gets bored and give up, or until he turned to dust himself. It stood up from the ground and glared at him, its eyes were dark and devoid of life. Sans waited patiently for its turn, preparing himself for another barrage of attacks that he would just avoid. It stared at him, as if it was contemplating on what he had said to it a while ago. It gave a tiny shake of its head and gripped its knife tightly. It died with seven bones sticking out of its chest.

*******

Sans was panting now, sweat dripping. He didn’t know how much longer he was going to last. He had at least 10 more turns before he’ll decide on doing his special attack. He placed his boney hands in the pockets of his jacket, and stared at the child. It was expertly twirling the knife between its fingers, smiling eerily at him. Sans’ grin tightened and his hands were shaking inside his pockets. If he could just strangle it, watch the life go out from its soulless eyes. He knew what the little brat was going to do, it kept dying at this part because it couldn’t jump high enough and evade the sharp bones about to impale it. Sans had wished countless times that he could change his attack patterns but by some mysterious force he couldn’t as long as they were in battle mode. He was trapped in this continuous loop of attacks as long as this timeline stands, making it possible for the kid to memorize his attacks and evade it; if he had his way, he would have pierced this brat’s heart as soon as it appeared at the SAVE point, this way it would be easier and maybe it would RESET the whole timeline and he might see his brother again.

“Why shouldn’t I?” it said, its voice was soft and harsh at the same time; menacing yet sultry. Sans took a step back; he stared at the kid, its voice unlike Frisk’s gentle and timid tones- this voice was loud and full of bravado, too old to be in a child’s body and was terribly familiar to Sans. Timelines were jumping back and forth that he could scarcely remember his past life, a life where he was just a young scientist working at the Core with Alphys and … and … someone else.

“*you can talk?” he said incredulously. The child rolled its eyes and placed a hand on its hips “I knew you were a comedian but I didn’t expect you to be that stupid.” It walked towards him slowly, sheathing its knife behind its back. “To answer your bloody question, I killed your brother because I can. I killed him because he was too naïve and innocent and here, innocence gets killed.” Every step it took made Sans twitch in anger and his bones shake. “I did it because I’m the demon who comes when its name is called.” They were inches apart now. Sans was rooted to the spot, eye sockets going dark, sweat forming on his skull. The demon was close enough for it to gently drag a fingernail across Sans’ exposed clavicles, breaking Sans from his trance. He jumped away from the demon, who just placed a finger on its lips, cursing himself for being too careless. He enveloped the child with his magic and the last thing he saw was a smug smile on its face and the sounds of bones cracking on the orange tiles and blood being spilled.

*******

“Seriously,” a voice said from a pillar behind Sans “It’s rude not to let others finish talking” Sans swore under his breath and turn to face it. He had been too distracted from the previous encounter that he didn’t notice that the kid had already RESET and managed to sneak up on him.

“*i don’t care about what brats like you think” Sans spat out. He summoned his Gaster Blasters and aimed it at the kid. He should just fire away but his curiosity was just nagging him. It placed a hand on its chest and feigned pain “That hurts my cold dead heart, dirtbag, but I should’ve known that.” It waved a dismissive hand and walked towards him “anyways, let me finish where I left off.” The demon took out its knife and smiled at him “My name is Chara, and I come when I’m called.”

That introduction was so absurd to Sans scoffed “*that ain’t true, sweetheart.” Chara raised an eyebrow at him “Why not?”

“*that dreemurr has been dead for a long time, i went to her funeral myself.” Sans raised his left hand at the demon, bones glowing cyan appeared behind him and the world slowly melted to black as he dragged them to battle “*i made sure she was gone” he muttered.

The demon just laughed at him as it casually tossed its knife in the air and catching it back again, the tip pointed at Sans. “Yeah, I know that. I was at the funeral too”

“*i never saw you there.” and he started his attack.

Chara already knew this song and dance; she knew it by heart by now. She enjoyed every sick minute of it; the way Sans looked at her with silent rage, the way his bones would pierce her body; the blood trickling, dripping, spilling out of her human host; the way her body is slammed onto the ground so hard, it cracked the tiles – she was truly a masochist to him but to only him. As masochistic as she is, the one she’s wanted to do the most is shove her knife into his beating soul, watch the light of his eye sockets disappear and let his dust slowly slip from her bloodied fingers; then she’ll do it again. And again. And again till the end of time.

“You really can’t remember I was there?” Chara asked him, innocently batting her eyelashes at him. He covered the whole floor with bones, so Chara was balancing precariously above him on one of the safer bone platforms, evading the incoming columns of bones. “I thought we had this sort of thing before” she calmly jumped off to the ground at the end of the barrage of bones.

Sans shrugged “*the only thing I can remember, kid,” his eye sockets darkened “is killing you.” Chara charged at him, knife raised close to the side of her face. She knew he would dodge it and he did – slash after slash, stab after stab, he evaded all her attacks with his metacarpals in his pockets. Chara withdrew for now, saving her energy for his future attacks. She saw him breathing and sweating hard but didn’t attack, so Chara used this opportunity to continue their long overdue conversation.

“I know you're smart and all, _comedian_ ” she spat at the last word as Sans raised a hand to attack “so figure this one out.” She smiled at him “one can’t possibly be absent at their own funeral.” 

The lights in Sans eye sockets appeared, brow bones scrunched in confusion, as his hand wavered “*what did you say?” he shook his head and gained his momentum back “*can’t hear you over the sound of you DYING”

He unleashed a hail of bones at her, she dodged them all, she was doing this thing for a while now, but one bone hit her foot, causing her take a little damage but it was draining her HP. She _knew_ it was the last attack but a lone bone caught her by surprise and sliced through the top of her shoulders. Chara yelped in pain, her HP began to drain faster, staying at an edgy number of 27. She clutched her injured shoulder, feeling the blood gush out. Her vision began to get fuzzy and she began to slightly sway from all the blood loss “That was cheating!” she yelled at Sans, who just shrugged and lazily winked “*no, it wasn’t. *just wanted another bone inside of you.”

Chara huffed and took out her last bisicle and began to lick the side of it slowly. “Anyways, might I add,” she reached the tip of the blue popsicle and bit it harshly “it was a very nice funeral.” She chewed as Sans eye socket twitched and sweated nervously “Such a moving ceremony. Tears were shed.”

“*who the hell do you think you are?!” Sans growled. Oh, he was mad now. He summoned his Gaster Blasters around Chara. There was no escaping this one; she’d better do it now.

“I already told you.” She tossed her knife nonchalantly behind her. The metallic clang resonated loudly, making Chara flinch. “My name is Ch-“

“*yeah, yeah” Sans interrupted “*you’re Chara and you-“

There was a sound of rustling cloth and Chara disappeared from the circle of death. Sans stumbled onto the floor in shock. He felt arms wrapped around him from his shoulders. A knife was clutched closely to his sternum. Sans felt her hot breath on the side of his skull as she whispered the words “and I come when I’m called.”

Sans aimed and fired every blaster at himself.


	2. Chapter 2

**Summary for the Chapter:**

> Sans reminiscences his past.

            He remembered it clearly. It was a particularly humid day at Hotland that day, not like it was any cooler before, but it was hot enough for Sans to remember it – and it wasn’t because of the weather too.

            “*i thought Asgore was supposed to come today?” Sans asked Alphys as he lounged at one of their Laboratory’s chairs with his shoes on the table.

            Alphys sighed. “He probably forgot all about it.” She then returned to reading one of her mangas.

            “*heh,” Sans sat upright and Alphys glared at him, already knowing what was going to happen “*it probably slipped his **_goat_** ”

            The yellow dinosaur lizard like monster just looked at him “Even for your standards that was terrible.”

            “*Yeah, that pun was **_baaaaad_** ” Sans guffawed as he bleated. Alphys slapped a clawed hand on her face “Oh my god, Sans.” She groaned “I should probably go and check on the portable reactor though, just in case he does show up.” She adjusted her glasses and hopped out of her chair, grumbling as she went “that’s better than listening to horrible puns.”

            Sans chuckled to himself and returned to his previous relaxing position. He decided to reward himself with a few minutes of rest after working for three whole nights. Before that he had worked for a week on another project his father gave him; he spent the whole week in the lab – eating, working and sleeping in it. He hasn’t seen Papyrus in weeks.

            _i should call him._ Sans thought _just to see how he’s doing._

            He dialed his younger brother’s number and Papyrus picked up on the second ring.

“SANS?” Papyrus’ shrill voice greeted him.

“*hey bro.” Sans lazily greeted “*just calling to say hi.”

“OH?” Papyrus paused before shouting happily “GREETINGS, MY DEAR BROTHER. I, THE GREAT PAPYRUS, WOULD LIKE TO ASK IF YOU’RE COMING HOME TO DINNER TONIGHT, FOR I, THE GREAT AND AMAZING CHEF, MADE AN EXTRAORDINARY DISH OF SPAGETTI.” Papyrus added in a sad tone “YOU HAVEN’T BEEN HOME FOR A WEEK NOW.”

Sans’ ever-present grin drooped a little “*heh, not sure bro. the ol’ King Fluffybuns hasn’t shown up to see our project yet.” Sans could feel his brother’s heart breaking over the phone “*but, i can stop over there to eat dinner with you.”

There was a loud gasp on the line “REALLY? YOU WOULD THAT FOR…FOR ME?!”

“*of course I would,” Sans’ grin picked up “*you’re my bro”

“ALRIGHT! I HAVE TO GO BROTHER. I, THE GREAT PAPYRUS, HAVE LESSONS WITH UNDYNE TODAY AND MUSN’T BE LATE”

            Sans ended the call with a chuckle and returned his phone inside the pockets of his lab coat. He should thank Undyne for being with his brother all the time, so Papyrus wouldn’t be too lonely. He sat back comfortably for a few minutes before he heard the footsteps approaching. He could hear Alphys stutter as she spoke “- It’s s-s-still a great honor, your Majesty. We-we understand the King is really busy nowadays.”

            “He is” a soft feminine voice said “Too busy to see…all of this.” the voice curtly said. Sans considered standing up for the mysterious guest, but he decided not to and even decided to close his eye sockets and wait. Sans felt them enter the room when Alphys introduced him “This is S-Sans.” Alphys saw him lounging there comfortably “Sans!” she hissed at him.

            Sans just opened one eye socket to greet their guest “*hiya…” he faltered when he saw who was with Alphys.

            She was petite, a little shorter than Alphys because of her thin physique. She had short brown hair with bangs framing her head. She had bright ruby red eyes that were angled in a way that she looked as if she had a permanent glare on her face. Her small lips turned into a scowl when she saw him. Her cheeks had a slight blush and… she was cute. She wore a yellow and green stripped sweater, brown shorts and black stockings with brown hiking boots. There was something unnerving about the way she held herself or the way she glared at him, that peaked Sans‘s curiosity but the most interesting part of her wasn’t her looks, but because she was… human.

            “*uh, Alphys.” Sans said nervously “*that’s a…” he looked sideways before saying “…human”

The girl crossed her arms in front of her “I’m well aware of that, skeleton.” She said abruptly “I don’t need a scientist to figure that out.”

            Sans raised his hands apologetically, but his eyes didn’t match his gesture. Forget about being cute, this kid was a brat. “*don’t need to be a little testy…” he waited for her to tell her name but all he got was a smug grin and a “Your Highness, is what you’re looking for.”

            He raised a boney eye brow at her “*are you **_royally_** like this?” she just started at him, haughtily “*never heard of a human princess around here.”

            “I’m Chara Dreemurr” She smirked, as Alphys fidgeted with her claws “Daughter of Asgore and Toriel Dreemurr, Rulers of the Underground. Sister to Asriel Dreemurr, heir to the throne.”

            Sans resisted the urge to roll his eyes at her _Got that memorize, haven’t you kid?_

            He had heard long ago on how the King and Queen adopted a fallen human child. He had never met the child before, as far as he can remember, with his father keeping him and his brother indoors the whole time when they were children. He heard that the King was considering the child to be the future adviser for their son one day when he comes of age. But along the years, he had heard that some monsters went missing over the course of the years the human came to them. All of them were rumours though. Nothing was confirmed.

            “And you’re nothing but the son of the Royal Scientist.” She laughed brusquely “Your work is not even remotely as close to your father’s work,” she placed a hand on her chest “That’s what I’ve heard, so don’t take it on me, bone face.”

            Every word that came out of Chara’s lips sent daggers into his soul, but he wasn’t going to let a brat like her get to him. He had always been in the constant shadow of Dr. W.D Gaster, he knew that the first time he started working at the Royal Laboratory, and nowadays he just ignores the comments.

Sans shrugged at her “*i’m working to the _bone_ here lady, cut me some slack. Monsters like Gasters are too _holey”_ he raised his palm “to be compared to ol’ me.” Alphys just sighed as Sans chuckled. Chara, on the other hand remained impassive. “*anyways, i don’t want to waste your precious time as well, _your Highness._ *so, let me show you our reactor.” Sans removed himself from his seat and went to the back to show the princess their project.

            It wasn’t his best, Sans was sure of it – the machine him and Gaster were working on was going to win that title – but he had to create something so that the King won’t fire him for being too lazy, and he had always wanted to create another alternative power source for the monsters, instead of using magic all the time.

            “*Alphys and I tried doing this portable reactor, something like the CORE but smaller, home-efficient and more stable than the one here in Hotland.” He decided to leave all the talking to him, receiving a grateful look from his lizard companion, and flipped open a switch “*we actually made this as a prototype for the CORE years before it was fully built, but we decided to give it another go once the CORE was stable.”

            Chara looked around and saw at the center of the room, on top of the table, amongst the clutter of tools and parts that she can’t recognize, was a large glass box with metal frames bolted to it. Inside was a glowing greenish crystal placed at a makeshift metal pedestal, connected to the metal framings. There was a collection of wires outside and was connected to a lightbulb. “So,” Chara slowly approached the table “it’s like a generator.” She was transfixed at the crystal. The closer she got the prettier it became. It wasn’t opaque green but transparent with a greenish hue to it; the whole surface was rough and covered in miniature green diamonds. Sans stepped closer to Chara, assuring that she won’t tamper with the wires; honestly, he didn’t know if the reactor will work, he’s just hoping that Alphys really checked on it pre-hand and didn’t go watch her anime shows. He stared at her as she looked in totally awe at the crystal. “It’s so beautiful” she breathed out.

            When she realized that Sans was too close to her, she straightened herself and gave a slight cough “I – I mean, where does the crystal come from? I’ve never seen the likes of it before” He gave her a weird look. _Hasn’t this kid been to Waterfall? Place is covered with this stuff._

“*waterfall” he said. _Although, Sans did find it in a secluded area when he was trying to be alone for a while._ Sans considered _purely coincidental, really._

            Chara stared at it a little more before crossing her arms again and raising an eyebrow “Well?” Let’s get started then.”  Sans turned away from her and began to press a few buttons to activate the reactor. He was about to press the final button when there was a loud cell phone ring. Sans saw Chara whip around to see what it was, her eyes wild, a hand under her sweater near her waist, looking as if she was ready to pounce at any moment. He saw something shiny or metal glint underneath it before it was concealed by the folds of her clothes. _Why was this human too jumpy?_ He wondered _it’s not like something’s gonna attack them…_ All of the sudden, Sans both eyes flashed cyan. _Something wasn’t right here._

            “Sorry!” Alphys apologized “I-it’s my fault. I’ll just t-take this.” She started to back away from them “Just… go on without me!” then she was off. Sans sighed. Typical of Alphys; probably faked a call to avoid being in the same room as this Dreemurr- I mean, Sans would too, given a chance-or maybe it was really a call. Sans would never know. This _Chara_ has this vibe that would send anyone she encountered running to the other direction and he knew she was hiding something.

He didn’t get this job from being dumb; he was lazy, not oblivious.

            The princess just rolled her eyes and went back to reactor “Go on” she said impatiently.

“*as you wish, _your highness_ ” then he pressed the switch and everything exploded.

**Notes for the Chapter:**

> *apologizes for the bad puns* I'm not good with humor. But I'll try my best in the future (and if any one would like to suggest very bad puns hahaha then please, do comment) \
> 
> **SPOILER FOR THE UT ENDING**
> 
> (In this fanfiction / AU: Chara didn't die the same age as Frisk [that's what I'm assuming her age was in the game].)


	3. Chapter 3

**Summary for the Chapter:**

> Sans is getting real tired of Chara's shit

Sans wished he could be anywhere but here. A place where the timeline is stable; there were no RESETS, no genocidal humans, his brother and his friends were alive again, and most of all, he wasn't doing anything.

He wanted to escape the Judgement Hall; but where would he go? His home contained nothing but remnants of a happier life he had.  Snowdin was like that as well. He had no choice but to stay here and wait. Maybe he could let the brat win this time.

               Sans shook his head. She was probably going to RESET and kill him again; he could see the burning desire from her eyes. No choice. He has to FIGHT. He looked near the entrance – the kid wasn't there. He looked behind him; nothing. He has been fighting three times now, after the trick that the kid pulled. She hasn't spoken to him ever since that fight.

               Where could that brat be? He thought. It's supposed to be here by now. His question was answered quickly as Chara strolled in casually; eating what looks like a Glamburger. Sans stood rigidly, watching her carefully. Chara didn't even spare him a glance. She kept gazing at the ceiling of the hall, shifting to look at the windows as she walked towards him. Sans observed her in irritation.

               "*those things will kill you, you know?" he said to her. She looked at him, eyebrows raised as she chewed.

               "Makes your job easier, no?" she remarked "You've always been lazy since the day I met you." She tossed the remaining burger into her mouth and threw the wrapper nonchalantly to the side "Although, you were rather active when in bed."

               "*don't talk about the past like we had one." he growled at her "*you're nothing but a demon possessing my friend"

               "Oh," Chara smirked "the question is which friend you're referring to."

               "*cut the bullcrap, i'm tired with all the riddles." he rolled his eye sockets at her as he pulled her into the Battle Area when she was close enough. The whole world faded completely into black and the familiar hum of his Gaster Blasters materialized behind him. He didn't bother doing his whole '*it's a beautiful day...' speech. Ever since the kid spoke to him, he noticed that he was out of the loop of usual dialogue. Little by little, he could add a little variation to his attacks, but they were mostly the same. Unless, the brat does something out of ordinary – such as the disappearing trick the last RESET- then he could do something different as well.

               "Don't you mean you're 'tired to the bone'?" When Chara noticed the lack of laughter from her one and only audience, she rolled her eyes and took out her knife. "Whatever, I've always hated your jokes. You're better without them."  She attacked first.

***

            "I'm getting bored." Chara whined at him when they were both out of breath. She had gotten a bit farther this time but her health was quickly dropping into a single digit. She mentally cursed at herself and at him.

               If I hadn't helped him achieve this Karmic Retribution, Chara thought bitterly I wouldn't be having this problem in the first place.

               She did a lot of things for Sans; things she would never do to anyone else or let anyone know about. She hated him with every fiber of her being and everything he does makes her want to kill him more.

               Sans panted "*you're in no position to say that." He had his boney hands on his knee caps- he looked so pathetic and exhausted. Who wouldn't be if you've been doing this for – who knows how long – and were fighting her, you would be too.

Normally, no one lasts in battle with Chara for too long but Sans was a curious case, you see. He is everything he is now in the first place because of her. "What position will you have me then?" she smiled at him "On the floor? The wall? Or maybe your room, if you're feeling a little Frisky" she laughed.

               Sans felt his own magic shock him. He spat at her "*you're disgusting." Sans summoned his Gaster Blasters and shot at her from both sides. Chara quickly evaded it; running towards him to get the momentum to make a jump to a floating platform. She jumped and caught the ledge, fingers gripping tightly. Sans looked up, irritated and slightly in awe, that she made the jump this time. She looked down at him and said "Just how you liked it." she winked at him before pulling herself up. He was thankful that he didn't have any organs, or else he would have vomited all over the black nothingness around them "*stop flirting with Frisk's body, you whore." he muttered under his breath "*it's wrong."

               Chara kept jumping from platform to platform to avoid getting blasted by the blasters "For a skeleton, you sure do have a dirty mouth."she called down "As far as I know, you were my bitch and not the other way around." Chara jumped down to the ground to safety but miscalculated and ended up in front of a Gaster Blaster. Chara's eyes widen from her mistake; stealing precious seconds before she stepped away to safety – the laser only inches from her head. The smell of singed hair filled her nostrils. The Gaster Blaster roared at her and dematerialized.  She glared at Sans, only to see him pointing at something behind her. Puzzled, she looked back but it was too late; a Gaster Blaster flew towards her at high velocity, sending her flying yards away.

               Oldest trick in the book,Sans chuckled as she harshly landed on its face at his feet. And the idiot fell for it. The kid's HP was low and was bloodied and bruised. She groaned in pain. Must have broken a few ribs, Sans thought But sadly, not all. He looked at the broken form "*whelp." he said "*i'm waiting."

Chara looked up at him, teeth stained with blood. She smiled at him weakly, almost mocking "Mercy?"

               "*sure, why not?" he shrugged. He knelt down to the ground and with a single finger, he raised its chin as it gave him a gritty, bloody smile. He leaned in close to its face, almost touching, and whispered "*just kidding" and a sharpened bone pierced its head

***

**Notes for the Chapter:**

> A/N: whelp, someone's getting a tad sadistic now.  
> Thank you to those who left kudos! They are very much appreciated. Sorry of it's a bit short, I had to cut the original into two chapters bc it became too long for me.


	4. Chapter 4

**Summary for the Chapter:**

> The reactor didn't work. Obviously.

It didn't work. Sans was sure of it because he was lying down on the cold laboratory ground, along with the rest of the lab's surroundings. The explosion may have been strong enough to blast the ceiling lights but, thankfully, not enough to bring down the ceiling itself. The shaft of lights were hanging precariously by the cables; sparking and flickering the whole time. Sans sat up to survey the damage he had caused. In the place of the prototype was nothing but shattered glass, melted cables, crystal fragments and a circle of soot the size of the box before. Curiously, it was wet. Sans looked down and saw that he was also soaked. He looked around and assumed that when the crystal tried to power the light bulb, it released too much energy, therefore breaking the said light bulb; the shattered glass hitting the crystal at probably a high velocity and . . . _boom_ \- there was probably some sort of magic in the crystal that triggered it to release torrents of water. He didn't count the crystal's energy level nor its fragileness. It was stupid to assume that he could just plug it in like that. Sans couldn't blame himself – this was a half-assed project that he needed to do to buy himself more time here at the Lab. He never even did the math here. Alphys should have, but Alphys' forte lay elsewhere. Robotics, maybe.

"*whelp" Sans said to no one in particular "*that sure was a _blast"_ He heard a groan somewhere to his right and quietly sighed in relief that the kid was still alive. Brat or not, the kid was still a princess; His father, the King, would never forgive him if he gets the royal princess killed because of his carelessness.

"That was awful." Chara groaned as she sat up. She was drenched with water from head to toe. It was like she took a jump into a freezing lake, fully clothed. She was thankful that the sweater she wore wasn't thin enough to be revealing but it clung to her like a second skin. Her brown hair was plastered against her head; the tips still dripping.

"*nah, i think it was kinda _the bomb_." Sans got up, twisting the fabric of his lab coat to get rid of the excess water "*a little too _explosive_ for my taste but it was okay."

Chara just rolled her eyes at him. She stood up, raising her the bottom of her sweater to mimic what the skeleton was doing to his coat. She noticed that tools were scattered onto the ground; some in huge puddles and countless ruined blueprints on the walls. "*i'll go and get Alphys. she's probably too far away to hear the explosion." Sans said "*don't touch anything." Sans began to walk out of the room as Chara glanced at the remnants of the prototype and her eyes went wide.

 _The crystal!_ She thought urgently. She ran towards the center table, not noticing the lights flickering nor it hanging dangerously above the table. Sans was already near the door when he heard a metallic groan; making him stop at his tracks and glance as the cable holding onto the light snapped and fell onto to the princess.

Sans cursed as he used his magic to teleport to the kid. Chara gave a surprised yelp as Sans grabbed her by the waist and pulled her towards him and they teleported away just as the shafts of light crashed where they were standing a while go. Sans raised his left hand to summoned his magic to create a shield to protect the both of them; fragments of glass and metal ricocheted against his blue aegis. Both of them had landed harshly onto the ground – Sans' right arm wrapped around Chara, who was still in shock and awe from the teleportation, as she sat between his femurs. She didn't notice that she had one hand held tightly on his metacarpals and another hand near his kneecaps. When the crash calmed down, Sans powered down his magic.

"*that was a close one." he sighed against Chara's hair. He tiredly place his other arm around her and placed his jaw on top her head. The sudden physical contact made Chara flinch and flustered. Sans realized what he did as he recoiled,but not fast enough to avoid Chara's head hitting his jaw.

"Ow!" Chara rubbed the spot where they had collided "That fucking hurt!"

Sans clutched his jaw, "*that was my jaw." It wasn't broken but both of Sans' eye sockets glowed blue and checked his HP anyways.

 _15/ 20,_ it said. _Whelp, it could have been worse._

He stole a quick glance at the princess just to see if she was doing alright. She was breathing shallowly, flustered and still soaked. She had a few cuts and bruises, nothing major. But Sans tried to discretely check on her HP as well.

 _82 / 92_ it said. His eye sockets grew wide as the blue flames glowed a bit brighter.

 _How can this kid have so much HP?_ He thought. _No human can have that much HP unless they're..._ Sans was just about to check her LOVE was when Chara abruptly looked at him. The flames died down immediately.

"What the hell are you looking at, skeleton?" she spat harshly.

"*looks like you're fine to me, your highness." Sans shrugged. He stood up, trying to shake off the unpleasant feeling of dread and smiled at the human girl "*a bit soaked to the bone like me, but alright" He held out a hand for her to grab on. Chara just glared at him for a few seconds before standing up, ignoring his offer.

"*we should get some new clothes." He dug his skeletal hands inside his lab pockets "don't want you getting hypothermia or something.

"Whatever." Chara's teeth began to shiver "As long as it's dry, it's fine with me." She wrapped her arms around herself "I can't just go to the Palace looking like this."

"*yeah." Sans and Chara walked out of the room "*i've got some _bone-dry_ clothes lying around here somewhere."

Chara shook her head "That wasn't even a pun."

"*at least, i'm trying to be _humerus_ _,_ regardless of the situation.

"I don't appreciate effort." Both of them were walking along the corridors, trailing water behind them "it's just another term for failing."

"*throw me a bone here, kid but why are you so pessimistic?" Sans raised one shoulder "*you've got to _lighten up_."

Chara stopped walking but Sans just kept on. "Did you just..." Chara pointed at him.

"*dropped that one on you?" Sans looked back and smiled at her. Chara opened her mouth to say something but thought against it and bit her lip instead, a trace of a smile along the corners of her mouth. "*glad you've been _enlightened_ by that."He gave a cheeky wink and turned away.

"You're insufferable." He heard her say before she walked past him. Sans swore he saw her blush grow redder but quickly dismissed the thought. He had better things to think of— like where would he get this princess some clothes.

**Notes for the Chapter:**

> A/N: Okay, I tried tickling my funny bone... that's it, x3 I tried. Scientist! Sans is cute and adorable and Chara is just... aaah. Can't wait for Chapter 6...it sooooo. hahahaa yes. I'll update maybe next week again - two chapters in one - just because I don't want to release Chapters 5 and 6 yet. Fluff lovers....be prepared - your chapter is getting closer. For the Sinners? (/laughs), I'll try my best to impress ya'll.


	5. Chapter 5

**Summary for the Chapter:**

> Chara sheds some light on their past.

Chara knew it was time. She was just bidding some more, letting her magic build up for the right moment—and it was the perfect moment to show to Sans what she was really capable of now.

               Waiting was easy —all she had to was wait until the right human comes along for her to possess their body. The possession itself was the hardest – a demon or spirit cannot possesses a body without their consent. She had to convince Frisk to let her use their body. It was hard at first; she hung around them as a ghost, showing them how to use a SAVE point and how to LOAD a SAVE, occasionally even helping them know who they were fighting against. Chara knew every monster – their characteristics and weaknesses- from the times when she was alive. Frisk was difficult, so to say. They were scared at first, accidentally killing a Froggit and Toriel on their first run. Chara went ballistic on them. Even if she was a demon, her memories of her adoptive mother still remained. So, being killed made Chara want to kill Frisk on the spot. But the kid cried silent tears as they sat with their backs on the Ruins door; facing Toriel's dust.

               When Chara calmed down, she gently rested a ghostly hand on Frisk's shoulder. It didn't feel anything, since she was a ghost, but Frisk appreciated the gesture and signed "I'm sorry. I didn't know." Then they began to tear up again.

               "No,no!" Chara frantically gestured, she didn't like it when children cried "Don't! There's a way to undo everything!"

               Frisk looked at her "What do you mean?"they signed. Chara explained to them how RESET works.

               Frisk did the first RESET after a very long time and Chara's plan was set in motion.

               She was already in the room behind him when Sans noticed her. Sans swivelled and saw her casually leaning on a pillar, slowly sucking on a blueberry bisicle. Sans stared at her in disbelief as she licked the side. Chara looked at him while her tongue was on the blue treat "I'm sorry." She beckoned the bisicle at him "Did you want some?"

               Sans turned his head to the side, hoping that Chara or whatever that thing is didn't notice the faint blue blush dusting his cheeks. He cleared his throat to regain the situation "*why do you bother with a bisicle?" he asked her "*it doesn't offer much health." he pointed out. He had a feeling he knew why and the demon answered his suspicions.

               "It's my favourite flavor." she smirked "Blueberry." She removed herself from pillar "Don't you remember? It was yours too."

               Sans sighed. He was exhausted; maybe a little break wouldn't hurt? They'll kill each other anyway so, why rush it? And he wanted answers.

               "*of course i don't remember." He tried "*i don't know who or what you are."

               "You really can't remember who I am?"

               Sans shrugged "*if you're not going to kill me yet, which i highly doubt it, then enlighten me then." He dragged them to battle once again.

               She didn't speak for the rest of the battle. She kept dodging his attacks but she was getting sloppy. When she attacked him, it was just a few slashes and she withdrew. Sans' inquisitiveness was nagging him "*i thought you were going to answer my question?" 

               Chara gave a short laugh as she drank some Sea Tea she kept in her pack "I never agreed to anything." This gave her a jolt of energy and her HP is acceptable enough. Sans summoned sharp bones and flew it towards her. She nimbly dodged every one, thanks to the Sea Tea.

               "Also, you never specified your answer." She raised her eyebrow "and since when did you start talking civil to me? It's strange, seeing I did kill all of our friends."

               "*would you prefer me doing THIS?" He wrapped his magic around her, lifting her from the ground and slamming her into a wall of bones. Chara's HP quickly depleted as she screamed in agony as the bones pierced her back. Sans brutally extracted her from the wall; tearing some of the material of her sweater and forced her again into the other side. By some twisted miracle, none of the bones directly pierced its heart but penetrated most of its flesh. It screamed in pain.

                 It startled, and as well as frightened, Sans that he was _enjoying_ this creature's misery. Maybe it was because he was had spent too much time with the demon or maybe this was his way of avenging his friends. He wanted this brat to scream, to bleed, to break everything inside of it- everything but kill it. He wanted it to suffer the way he did. Again and again and...

_Papyrus would have been disappointed in me_

                  That single thought forced Sans out of his sadistic fantasies. The furious glowing in his eye socket turned dark and Chara was dropped to the ground. The Judgement Hall was reappearing again. They were out of the battle phase. Sans stared at his feet; eye sockets dark. What has he become? Didn't he swear that he would never revert to his old ways?

_That was my last promise to her._

                      "And he remembered." Chara said, voice still confident and boisterous regardless of the state of her body.  She forced herself up; balancing herself on her elbows as she looked at the skeleton. Sans didn't notice that he had spoken aloud. How was she still alive? He couldn't check what her HP currently was but from the attack and the fall, she would have been dead already.

"Did you know that," Chara shakily got onto her knees " if a human as enough Determination inside a body, it could convert it and create magic?"

Sans shook his head "*impossible. it can never happen, unless-"

"-the human has knowledge about magical arts, correct." Chara finished.

It was just a theory. From his researches, he theorized that since the human soul can persist even after death- through the power of Determination- with enough DT and knowledge it could use DT-powered magic.  "*like i said, sweetheart" Sans looked at her dead in the eye "*impossible."

Chara stood up, clothes singed and torn, smiling at the ground "Is it really?


	6. Chapter 6

**Summary for the Chapter:**

> Chara gets caught up in a situation.

  
"You expect me to wear _this_?" Chara lifted the piece of clothing by the edges like it was some sort of radioactive substance. She knew who owned it and she would never wear this unless it was life or death.

"I-I-I'm sorry, your highness."'Alphys apologized "Sans told me that this was the only clean piece of clothing he had."

Chara was shivering from the cold. Whatever the crystal spouted, it was freakishly cold. It didn't help that her sweater was made out of wool and spider silk, making it super absorbent, nor the fact that she was wearing shorts and that even her undergarments were soaked. She sighed, it was either this or walking like this to the castle; Toriel would go ballistic on her – saying that this was not the proper etiquette of a young lady or of a princess, but she'll take care of her anyway; Asriel too maybe – he had always been a little to overprotective after reaching 18 – or maybe he'll be the mischievous older brother and would take a picture of her, never letting her forget this moment. She looked at clothes given to her by the stuttering lizard-monster – was it Alphys?

It was blue zip-up hoodie with white fur lining at the hood and a pair of black basketball shorts. All were clean, thankfully, but were obviously of Sans'.  
She sighed remorsefully and looked at Alphys "Do you have _any_ other clothes?"

Alphys thought for a moment "I have a –a- spare dress in my locker – that's the only clean item I have." she muttered to herself "The rest are just dirty lab coats."

"A spare lab coat maybe?" Chara desperately asked.

She shook her head "A-All of them are dirty as well. I don't know if the other interns have some, but I highly doubt it."she hastily added "Your highness."

Was she desperate enough to wear some worn out, dirty and probably contaminated lab coat rather than being embarrassed to wear his clothing? Nope. She still has her pride to take care off. She was still royalty, after all.

She could order Alphys to get her some clothing from the palace but that would take time; she'll have to sit around in her wet clothes longer – she wouldn't have that. She was already feeling traces of a cold coming on.

She contemplated it for a bit more as Alphys stood nervously in front of Chara.

"What color is your dress?"

"Um, pink?"

Okay, that was it. "Where can I change my clothes?"

Sans returned to the ruined room after he brought the clothes to Alphys. He wouldn't want to stand in the argument with her royal pain in the ass. He shook his head, placing a tired hand on his skull. The whole place was a wreck.

The blueprints that he had drawn by hand, along with the crude ones made by the interns, were hopeless. He hoped that none of them were too important to his father. Sans could always remake his plans, but Dr. Gaster was too meticulous of his work that it takes him forever to complete one blueprint. Sans sighed, at least he could take care of the other damages himself.

He summoned his magic using his psychokinesis to pick up the scattered objects and put them in their rightful places; gathering the shards of glass and placing them in a neat pile. Sans remembered how he practically wrapped his arms around Chara. She felt so soft; the feeling of her skin on his bones was electrifying. It was a curious feeling, seeing that that was the first time he touched a human before. He knew what humans were made out of – blood, muscles, and organs and underneath it all were bones. He looked at his metacarpals, both were glowing bright blue from the magic. To think that the princess held these...

All the floating objects suddenly dropped into the ground as Sans' cheekbones were dusted with blue. He cursed at the harsh sound and quickly returned to his task. What was he thinking? Sans shook his head. He knew his magic was critically in line with his emotions. So, why did thinking of her mess with it? As he finished cleaning up, he hastily walked out of the room.

 _You're just curious about her,_ Sans mentally told himself _It's_ _not that kind of infatuation, and besides you just met her today._

He was probably right. In truth, no one knows much about the mysterious human princess either. She was always in the castle for all they knew. Dr. Gaster mentioned her one or three times but more on the topic of wondering if the King would allow him to do experiments on her. Regardless of his opinions on humans –or his lack of hers - , Sans would quietly disapprove of his father's inquisitive nature. The _experiments_ that Dr. Gaster would like to do would be excruciatingly painful to someone.

 _But it would serve for a better cause_ A voice inside his head told him.

Sans shook his head. It was too sadistic, too cruel. He suddenly remembered about Chara's HP. Why was it extremely high for her? It can be, in some cases, due to magic training but a human cannot perform magic; everyone knows that. Humans just don't have the natural capacity for it. _Maybe it's not natural._ The idea of a human being able to use magic, piqued Sans' interest. He'd look more into that later.

Chara looked at the set of clothes and sighed. She stood alone in a room with a set of movable trays and shelves filled with a collection of items that she couldn't recognize. A full-body mirror stood at the corner of the spare room. It was too crowded for her liking but Alphys told her all of the rooms were being used or contained some fragile experiment or whatever.

She lifted the shorts in front of her. It looked alright, she guessed. It was better than nothing. She removed her cold boots, shorts and black stockings. She contemplated whether she wanted to be in soaked underwear the whole time, losing the sense of why she would change the first place, or risk just being in these basketball shorts.

"Why does this shit keep happening to me?" Chara sighed and removed her underwear. She slipped into the shorts. Chara knew that the skeleton was short in monster standards but he was still a head taller than her; she was 4'11 and he was 5'5 or 5'6, so the shorts were too large on her. She pulled at the drawstrings of the basketball shorts till the end but it hanged a little low on Chara's hips because that was the only place wide enough for it to fit. She groaned in frustration as she tied the strings as tight as possible. _This is why I hate being freaking small._

Annoyed by her situation and the sheer smallness of the room, she hastily removed her sweater. She pulled it up her head but when she was about pull it over, it got stuck at the countless objects on the shelves. Chara struggled to get it out—she got it a few inches above, but she was far from done. She couldn't see anything because her damp sweater was stuck near her head; only her mouth, her chest and abdomen was exposed. She struggled further, slamming onto the shelves backwards to loosen something but backfired on her as something fell down above her.

"Ow! FUCK." She hissed in pain. She tried to do something else and jumped sidewards, only to get hit by something from the other side. "Ah, shit!" she started and began to shout in various obscenities.

There was suddenly a knock on the door "*um hello? ya alright there, buddy?"

"DO I SOUND OKAY TO YOU?!" She shouted through the door. "DO I SOUND FUCKING ALRIHGT?!"

The voice let out a chuckle "*i guess not?"

"FUCK WHOEVER YOU ARE AND HELP ME, YOU FUCKING MORON."

She was too furious to notice that the one she was talking to was the one she doesn't want to see. Sans was too busy laughing at her outburst that even he couldn't identify Chara's voice when it was shouting at him.

"*okay, okay," he grabbed the knob and turned "*i'm coming in."

What greeted Sans was a practically half-naked Chara whose woolen sweater was caught in a broken rake stuck at her head; a mini vacuum and trashcan at her feet. She was also practically shaking in rage and from what Sans can assume was embarrassment.

"*i see that you're in a _bind_." A deep baritone greeted Chara "*something _raking_ you, princess?"

"Sans?" Chara stopped moving and angled her body to where the voice came from.

"*to your rescue, my lady" Sans laughed. He stared at her human body curiously- it was covered, in well, skin; she may be small but she was curvy and was wearing his shorts, very low on her waist. Her body was covered with a sheen of water, glistening from the single lightbulb hanging directly above them. Sans blushed as his eyes drifted up to her chest – where he noticed that she was wearing a deep blue navy bra-

 _Oh_ _okay, buddy_ Sans averted his eyes _Time to stop._

As much as she was mortified of this situation, she was thankful that the sweater was covering most of her face because she couldn't have been redder than now.

Chara stayed silent for a while and felt as if Sans was raising a brow bone at her "Fuck you and get me out of here." she said silently "And stop looking!" she added hastily.

Sans chuckled "*how can i help you if i can't see you?" He stepped forward, closing the distance between them. Chara  
shivered from the cold air touching her bare body.

"Quit your stupid remarks and just help me!" She ordered him "and shut up!"

He just rolled his eye sockets at her and raised his hands to untangle the cloth "*someone has been a little _knotty_."

"Fuck you, Sans." Chara whispered as she felt her face grew hotter.

"*you're too _tied up_ , princess." Sans immediately said, without thinking "*it would be rude of me to take advantage of a damsel – in – dis ** _dress_** " he blushed profusely after realizing what he just said. He was mentally shouting at himself to shut up before he could say anything that he might regret later on.

When Sans got the sweater out of the rake, Chara quickly pulled it off and covered her chest. Both of them stared at each other for a few seconds before Chara said "Well?!" she screamed "GET OUT!" Sans snapped out of his reverie and stuttered apologies to her; tripping on the trash can and vacuum on the way out. "*sorry." He was already half way the out the door when he couldn't help but say "*nice bra, though."

"GET THE F U C K O U T " She threw her sweater at his face but Sans was long gone by then.

**Notes for the Chapter:**

> [*Sorry if it's a bit long]


	7. Chapter 7

Sans did not like how the demon was smiling at him. Not that he had liked it before but he surely despises it now; he especially did not like the way it was talking about magic and determination.

"*you're not making sense, sweetheart" he said nonchalantly, hoping it wouldn't see him sweating buckets "*like i told you, magic doesn't work on humans like yourself."

It just looked at him with malice and...excitement "Oh, are you really sure I'm still human? I haven't been human in a very long time, Sans." It purred "and I'm no ordinary demon either."

"*oh?" Sans smirked "*so you're an extraordinary demon then? what's the difference?" he pointed at it in general "you're shorter than ordinary demons?" He avoided thinking that he was obviously insulting Frisk, literally a short kid who barely reaches his chest.

Chara closed her eyes in annoyance "Says the shortest monster in the whole underground."

"*temmies are shorter than me." Sans pointed out. He was enjoying this banter "and a whole lot dumber than me."

"So, you do admit you're dumb?"

"*sweetheart, do i look like i give a shit?"

Chara strolled closer to him "You'll care a whole lot about me after this." she said enigmatically.

Sans raised a brow bone "*after what? after you grow five inches so you could reach me?" the following banter died on Sans' boney smile when that mysterious black and red smoke gathered at Chara's feet. The smoke looked as if it was coming directly from the demon.

"You may have killed me hundreds of times, darling." The smoke grew thicker "But I still have some tricks up my sleeve."

Sans immediately summoned his Gaster Blasters, two on each side of him and one directly above his skull and fired his lasers at the demon. The smoke at its feet shot up at the kid and solidified, protecting it from the blasts. Sans summoned more behind the demon and fired but the smoke blocked and solidified into a swirl of red and black. His eye socket was burning blue and cyan, almost too painful for him, as he summoned every blaster he can and fired it at Chara.

The smoke circled and enclosed Chara, as it absorbed the magic being fired at it. Sans may be strong but he wasn't strong enough to hold the blast. It seemed like an eternity to him and only minutes to her when he stopped firing, every inch of his magic spent. He collapsed on his shaking kneecaps; his hands on the floor of the Judgement Hall.

The ball of smoke melted, revealing an unharmed and smug Chara, remaining at her feet. She walked slowly towards Sans, reveling at his exhaustion.

"Sorry to tire you out, darling." Chara said sweetly "I just want your focus on me."

Sans panted "*i don't understand." He shook his head, still breathing heavily "*what are you?"

"You'll see."

The black and red liquid slowly crawled up to her, covering her in darkness until it reached her neck and gave Sans her sweetest smile—that even startled him—before she was completely enveloped in darkness. Sans stared at the black form in horror as it grew taller and more skinner. The black goo began to disappear, starting from the bottom and slowly going up. It revealed a set of flawless white legs in brown hikers boots, the clothes were Frisk's but was torn like before and was too small for the curvaceous body and barely covered her chest; her hair was a lighter shade of brown, cut short behind but the front locks of her hair was long, reaching past her shoulders. The girl was already close to him, but has not revealed its face. Sans knew in his soul that he knew this person but refused to acknowledge that she was standing in front of him.

"I'd like to thank you for the magic you gave me a while ago." As Chara Dreemurr's face was revealed; red eyes glinting "I didn't even need the magic I originally reserved for you." She clicked her tongue "Such a waste, but it doesn't matter."

Sans stared at her in a mix of horror, bewilderment and regret "Chara." he just said, as he sat onto the floor. This was _his_ Chara; the one that he had once loved and cared for, the one he taught the wonders of his world, the one he had entrusted his whole being too—and the one that he had gotten killed.

Chara knelt down between his femurs and gently a hand on Sans' jaw, lifting so he looked at her "Sans." she said quietly. "It's been too long." She pressed her lips against his teeth.

Sans knew this was wrong; he was letting this...murderer _touch_ him, kiss him even. He let her press her soft lips onto his teeth; allowing her hands caress his jaw and trail along to the back of his skull. This was still the demon who killed his brother and his family. But nevertheless, he slowly wrapped his hands around her hips and pulled her closer to him. He felt the demon smile between the kisses as her tongue began to lick his teeth teasingly. Sans knew he should shove this...demon away from him; kill it before it can do any worse. Her lips kept parting and kissing him, her tongue coaxing his own to taste her, until his magic was going haywire. The most difficult thing about his magic is that it was closely tied with his emotions. And when he felt _extreme_ emotions, he loses control of it. The only person who made him feel this way was Chara.

 _Chara,_ a single name that brought a hundred memories, emotions and heartache. He remembered the day of the funeral when they had to burn her body and scatter her ashes at the yellow buttercups. Chara felt Sans' reluctance and drew away to look at him, her hands sliding to his shoulder blades. He looked blankly to the side; remembering that technically she was still dead.

Chara sighed exasperatedly; she didn't just use her magic to get her body again just so she could get some half-assed kiss from him. Chara abruptly stood up, returning Sans' attention back at her. She placed both of her legs on the Sans' hips and sat harshly back down, straddling him. She forcefully pressed her lips against his teeth; hoping for a better response this time. Her hands traveled downwards and slid themselves under the fabric of Sans' shirt and hoodie. She felt Sans shiver as her fingers slowly caressed his outer ribs. Chara felt Sans moan into her mouth; his fingers digging deep into her bare flesh. She had always liked the way Sans' bones felt on her skin. Chara slightly scratched at his bones, Sans shuddering in response. She used this opportunity to bite down on his exposed collarbones. Sans groaned, his fingers dug deeper; the pressure and the sound of Sans' groans excited Chara, making her suck and lick roughly on his bones.

Sans wanted to stop. He had to return the bite to Chara out of frustration. He would never admit that he liked how she let out a long high moan that resonated along the Judgement Hall, how her hips rocked against his pelvis as he bit deeper, blood oozing and mixing with her sweat. He heard her whimper against the side of his skull. He hissed as her fingers slipped through his ribs. Sans opened his mouth and used his magic to summon a new appendage. His bluish, barely solid tongue licked at the wound. Chara begin to thrash as his dripping ectoplasm begin to drip in rivulets down her shoulder, to her lap and inside of her through the bite wound. Everything his magic touches felt like she was burning, setting her nerves on fire. She tightly gripped at him as he hungrily lapped at the wound, biting her lip to suppress her moans; no, she wouldn't give in so easily to him. With all of her strength, she easily pushed Sans to the floor of the Judgement Hall. She sat on him, grinding his pelvic bones till his tongue lolled out to the side of his mouth and his short canines were showing and his metacarpals were bruising the side of her exposed hips. She leaned down and took his tongue inside of her mouth.

It was just like how Chara remembered it tasted like – Ketchup, blueberries and magic. The magic was the best part. As their tongue suck and mingle, Sans' hands begin to wander lower. Chara might have liked it but she only had a few moments and she wanted to taste all of him. Using her magic, the red-black smoke grabbed his hands and pulled it above him. The smoke slipped under him like a thin sheet of darkness and kept him stable for her. Sans' face looked at her confused and terrified before it quickly contorted into erratic panting and pleasure as Chara ripped the middle of his shirt with her magic and gave Sans' sternum a strong lick. She began to rub his inner ribs with both of her hands then moved the other hand to the outside. She licked each and every protrusion in his spine and soon enough, Sans was drooling mess. As Chara worked her way down, she pulled down his shorts till his iliac crest were exposed. She began softly caressing it, earning quiet whimpers from him that climaxed into screams as she rubbed furiously at his ilium till it was getting harder for her to restrain him.

She grinned at the quivering form beneath her, relishing the dominance she has "Not so used to being helpless now, are we?" she snapped her fingers and the darkness beneath Sans elongated into black tentacles and slipped between his ribs to every orifice in his whole body and held him down. The sensation was indescribable – it was burning hot and freezing cold; pleasure bordering onto pain; it was light and airy, the fondest memories they had and... it was also the dark. The darkness that consumed the both of them and left nothing but pain.

"Feel that?" she wrapped her fingers around his spine as she sat on his pubis. Sans clenched his teeth, a weak attempt to dull the pain. "Can you, Sansy? Oh, I sure can" she squeezed tightly, an audible crack was heard "The darkness; the abyss that I was in for years, the one we thought had consumed me," she smiled down at his dark sockets and grimace "It never left and now?" she willed the dark appendage to grab the discarded knife. She gripped the weapon with both hands and raised it above her, face hidden. Sans' gaze went to the blade. It had a dark sheen to it and that was the moment he knew there was no coming back from this one. This may looked like Chara Dreemurr but this wasn't the woman she knew all those years.

"*do it" Sans voice quivered from the pain "*kill me. that's what you want, right? you filthy demon" liquid darkness began to rivulet down Chara's face "*WHAT ARE YOU WAITING FOR?!"

"Kill you?" her voice was barely a whisper that brought Sans to a deadly chill "If I kill you," she raised her head, the blackness had taken the whites in her eyes and were spilling out onto her pale face. She smiled but it was wrong; too wide, too horrifying. A red snake like tongue came out of the abyss of her mouth and licked the dripping black tears. "I would LOVE to kill you, my love," she lowered the knife "but where's the fun in that?" She laughed a terrible laugh and, with that, red rained upon them.

Sans could never forget the taste.

**Notes for the Chapter:**

> If you managed to read it without cringing, well, wow. I sure couldn't. Literally first time doing stuff like these, that's why I haven't updated in awhile (that and I was in a theater production of Les Miserables [Madame Thernardier ya'll] and didn't have enough free time to finish it). Sorry and hey, I'm kinda back?  
> Kudos if you like it (check out on Wattpad too, if you like. It's there too)


	8. Chapter 8

Sans tried to keep his head as blank as possible on his way back. It wasn’t like he wasn’t  trying hard enough but the image of her just kept popping back and left him blushing madly blue. He shoved his hands into his lab pockets; since keeping his mind empty wasn’t doing much, he began to think a different solution for his generation problem.

    The crystal either overloaded from the power from the lab or it was the other way around? It made sense that it would produce water since it came from Waterfall but how could such piece of crystal able to produce such volumes of water? If he used a bigger, and possibly a stronger crystal, would it withstand the power of lab or would it cause a larger explosion? He should sample the water residues and remnants of the crystal to be sure if there were still some left. Sans stopped walking; he could always get more on his way home. He smiled – he might see Papyrus after all- and continued on.    

    As he dwelled longer on the possible components of the crystal, it drifted back to the princess. Why was she so fascinated by it? It did look okay to Sans, a simple crystal studded with small diamonds, nothing fancy. But the princess was simply enthralled by it.

    _Huh,_ He smirked _maybe I could make a cute necklace for_ -

    Sans shook his head as if to shake the memories from his head. He shouldn’t be thinking of her at all. It would cause nothing but trouble for him and he was in already in huge trouble for almost destroying a lab. It wasn’t like he was the first one who endangered his life and of others but he had a reputation to uphold. He wasn’t some monster on their first day, doing petty science experiments –He was one of the top scientists here; he was considered a legend amongst his peers for being equal parts genius and lazy bones. More importantly, he was the Royal Scientist’s son. Well, his only son, according to him.

    Papyrus never went on the scientific route, venturing on to a more adventurous path of life. He was smart, innocent and kind and wanted to become a Royal Guard so that he would protect and be loved by everyone. Gaster didn’t approve of his decision, choosing to refuse his existence from there on. Sans supported his brother’s dream. It was comforting to see that Papyrus was lovable by all and had this bottomless optimism. Sans didn’t have to worry that he would end up like him – stressed with everything and a constant disappointment to his father.

    That didn’t jar him as much as before; humor helped him a lot. Instead of moping all the time after Gaster reprimands him or when his experiments fail, he jokes around with his co-workers instead. Mostly about their uptight boss. He was so deep in his thoughts about the man he hated the most that he didn’t notice that he had bumped into him.

    “Not looking where you’re supposed to, hmm?” Dr. Gaster peered down on him, through his glasses, voice abysmally deep.  Dr. W.D. Gaster was a tall skeletal monster with an old singed lab coat over a grey turtle and black slacks. His palms had a gaping hole in the middle of them, carrying several books and blueprints while a pair of hands – similar to his- floated beside him.

Sans snapped his head up and stuttered “*fath-uhm- Dr. Gaster.” He attempted for a smile but it came off weak and strange but Gaster was never the type to be emotionally sensitive anyway.

    “The king was supposed to arrive earlier,” his extra floating hands removed his glasses, cleaning them with a small rag before tucking them into one of his numerous lab pockets “Why?”

 _Always direct to the point, aren’t we?_ He thought bitterly _pleasantries was always lost to you, Doctor._

    “*he wasn’t able to come.” Sans glared at the floating hands behind his father’s back, he had always despised them “*he sent someone else instead”

    “Really? How unusual.” Gaster looked away, deep in thought, “He’s usually excited about coming down here, eager for reports.” He reverted his attention back to Sans, sneering “It made sense that he wouldn’t waste his time on your pet projects.”

    Sans kept his mouth shut and his gaze downwards. It was no use talking back at him, he would just use his words against him. He wished that he would just leave and stop asking questions. He didn’t want to tell his father that there was a live human walking inside his lab. Sans cursed himself that he told him that someone else came.

    “Who did he sent instead?”

    He flinched, hoping that Gaster wouldn’t notice his hesitance being more than usual. Should he tell him that the Royal Princess was here and most likely wearing his clothes? Tell him that his experiment failed? If he just told him the truth, that would save him a whole lot of trouble but… why should he protect her anyway? She was a pain in the ass the moment he saw her. What was stopping him from telling his father? He wasn’t obligated to…

    “Well?” Gaster’s hands tapped impatiently on his books “Are you speech impaired as you are lazy?”

    “*some flame guard monster delivered a message and left as soon.” He shrugged. Gaster looked at him a few more seconds, probably pondering on his son’s answer, and left without a word. Sans started walking away as well.

    When he turned around the corner, he placed his back against the wall and sighed deeply. Gaster might be the most intelligent monster in the Underground but Sans was smarter and a better liar than him.

\---

               “Y-You look…uh… okay, your majesty” Alphys assured Chara when she asked how she looked “It’s a good fit, really. I thought they would be too big on you, ah, your highness” she smiled awkwardly at her.

    Chara looked down on herself, pouting “It’s better than soaking ones.

    They were in Alphys and Sans’ common office where both of them stayed most of the time when they weren’t in their own laboratories or they weren’t teaching. Honestly, the blue hoodie was comfy, maybe a bit too long on the sleeves but it was alright. It smelled like fresh laundry but had a distinct, indescribable dry scent to it. Curious, Chara hefted the arm sleeve to her nose, identifying the scent. It was faint, overpowered by the lemon detergent but it was similar to the smell of paper, like the old books from the Royal Library Toriel sometimes let her read. Oddly, it was comforting. Chara heard a small ‘eeep’ from a giggling Alphys, who tried to conceal it by covering her snout with her claws.

    She blushed deep red, remembering who owns the hoodie. She ducked her head in embarrassment. Alphys quietly giggled “You were…”

    “No, I wasn’t” Chara denied.

    This made Alphys giggle louder “Ah, yes you were.”

    “No. I. Wasn’t” she stressed every word “I would never do something so… disgusting”

    “AHhhhH, that is so tsundere” Alphys chuckled as Chara madly shook her head.

Alphys couldn’t believe that this distant, mysterious princess was being too adorable. She looked like the protagonist of the romantic animes she watched – blushing and denying. Just a while ago Alphys was insanely terrified of a human girl as tall as her but now her red face was a stark contrast to Sans’ blue hoodie that made Alphys internally screamed.

 _Goodbye, Asgore, and Toriel, there’ll be a new ship in the Underground_ Alphys told herself.

 “This is so going on my blog. Oh, don’t worry, your highness, I won’t tell him that you were sme-“

    “I WASN’T” Chara shouted, blushing madly. She squatted on the floor, hood concealing her head, hands on her head “SHUT UP. I WASN’T.”

    “*you weren’t what now?” A voice asked in front of Chara.  A bit too close, perhaps. She looked up and was looking eye to eye with the skeleton monster. Alphys took this as her cue to leave, squealing internally. The two protagonist should talk about their burning passions for each other alone. As soon as she left the room, she rang up her phone “Oh.My.Gosh. Undyne, you would never believe what just happened…”

               Sans helped Chara up after she fell backwards in shock “*are you okay?” he asked. Chara brushed his hand away and stood up by herself. “I’m okay, I don’t need your assistance.”

    Sans tucked his hands in his lab coat’s pockets “*well, I _hoodien’t_ be so sure about that” he looked at her clothes “*you’re looking a bit _blue_ , _shorts_ -ing _bra_ -thering you?”

    Chara glared at him but like always, it had no effect on him “Are you done? You already mentioned everything”

 Sans held his hands up “*wait, I think I have one more. *seemed like you _fell_ for me, a bit soon, wasn’t it?” He smiled at her “*okay, I’m done.”

    “*you look…” Sans searched for the word “acceptable.”

    Chara rolled her eyes at him as she rubbed her cold feet, sitting on the boxes occupying the cluttered office. “That’s the best you can say?” She couldn’t wear her socks nor her boots because they were still soaking wet. The cold tiles of the Lab weren't helping her gather warmth either.

    Sans shrugged “*what do you want me to say? you’re wearing my clothes.” he walked towards his desk “*it doesn’t really garner respect, now does it?”

    She huffed “No, it doesn’t” Chara looked at Sans, who was searching for something at the corner of the room “What are you looking for?”

    “*something useful.” he answered.

    Chara scoffed “In this mess? Nothing looks useful here, including yourself”

    “*wow, very nice, your highness” Sans sarcastically replied “*seeing that you, yourself, is also in this messy room it only means that you’re useless as well.”

    “How dare you, you fuc-“ Chara began, standing only to be slapped by a hurtled furry object.

    “*language, princess” Sans tsked “*I thought you had manners.”

    “Only to people who deserve it” She countered.

    “*same here, princess.” He retorted “*it’s for your feet by the way, if you haven’t figured it yet.”

    “My what?” Chara looked down and saw a pair of pink furry slippers lying on the floor “Oh.”

    Sans looked at her expectantly “*well? what are you waiting for?”

    Should she wear them? She was already wearing his clothes. What’s a pair of slippers to her? She sighed and slipped into them. They were rougher than she expected on the inside, a bit old and worn out.

    “Happy?” Chara placed her hands on her hips.

    He grinned “*now, you look to mine.” There was an awkward pause before Sans realized what he said. “*i meant, you look like me. “he chuckled nervously, blushing blue “yeah, heh.”

    “HHhhng, OTP-material.” Alphys shrieked from the doorway “You guys are, like, so meant to be!”

    Chara face palmed, cheeks flushed, and Sans looked away from them, hiding a hint of a smile. But it didn’t meant anything, he was always grinning anyways…right?

**Notes for the Chapter:**

> [I'm bad at jokes and puns, please stop me. help me.]


	9. Chapter 9

  
It was dark – it always has been and it will always be.

**"I thought you had it under control?"**

_"I did! But you were getting too unstable, someone had to remind you who's in control"_

**"'unstable'?! You're calling me unstable? Slitting your own throat and someone else are two completely different things."**

_"Really? I wasn't the one who asked for another chance"_

**"Neither did I. No one wanted this; you best better remember that.** "

_"It's either that...or are you going soft?"_

**"How dare you say that to me, you insignificant piece of shit!"**

_"-I'm just judging on the fact that you let-"_

**"You are NOTHING without me. You'd crumble to back to dust without my help!"**

_"-him alive. That wasn't part of the plan. You were supposed to do-"_

**"You won't even exist without me! How dare you-"**

_"-what you were told. Since you're nothing but a waste."_

**". . ."**

_"You're the insignificant, useless speck in this world. They were right about you, you know? Abandoning you like that? A helpless soul trapped in that cave?"_

**". . . "**

_"What? Finally shutting up? Finally. Let me tell you, do you know what happens to the meek? You of all people should know"_

**". . . "**

_"Answer me. What happens to the weak and the submissive?"_

**"It gets killed."**

" _NO, those who possess even the slightest shred of weakness gets S L A U G H T E R E D"_

**". . . "**

"Do you understand these words I'm saying?"

**". . . yes."**

_"Good, that means you know what you're supposed to do."_

But it didn't mean that it was going to last forever

**Author's Note:**

> So... This is my first Undertale fanfic. I've been in this fandom since December 2015 and after I discovered about the Genocide Route (still playing it - can't defeat Undyne) I got obsessed with 'Chara' and Sans. There wasn't enough fanfics (nay, there were almost none) so I decided to make one myself! I don't usually do fanfics but Undertale urged me to go on create!
> 
> Updates are when I like it because I'm normally working on my original work on Wattpad (@InfiniteGoddess Ya'll) but I'll try and be in the mood when I can. 
> 
> *apologizes profusely for future grammatical errors, bad puns and confusing plot lines*  
> *but accepts comments and suggestions; criticisms and other stuff*


End file.
